Examples of ways to wait for promises

promise_all.js

// Promise.all only resolves when all Promises in the array passed in are resolved, and returns the array of resolved values.
const { setTimeout } = require('timers/promises');

const promise1 = setTimeout(100, 'Promise 1 resolved');
const promise2 = setTimeout(200, 'Promise 2 resolved');
const promise3 = setTimeout(300, 'Promise 3 resolved');

async function examplePromiseAll() {
  try {
    const results = await Promise.all([promise1, promise2, promise3]);
    console.log(results); // Expected output: ["Promise 1 resolved", "Promise 2 resolved", "Promise 3 resolved"]
  } catch (error) {
    console.error(error);
  }
}

examplePromiseAll();

promise_all_reject.js

// Promise.all If any Promise inside the iterator rejects, Promise.all rejects.
const { setTimeout } = require('timers/promises');

const promise1 = setTimeout(100, 'Promise 1 resolved');
const promise2 = setTimeout(200).then(() => { throw new Error('Promise 2 rejected'); });
const promise3 = setTimeout(300, 'Promise 3 resolved');

async function examplePromiseAllWithRejection() {
  try {
    const results = await Promise.all([promise1, promise2, promise3]);
    console.log(results);
  } catch (error) {
    console.error(error.message); // Expected output: "Promise 2 rejected"
  }
}

examplePromiseAllWithRejection();

promise_any.js

// Promise.any is settled as soon as any of the promises you feed it is fulfilled or they are all rejected.
const { setTimeout } = require('timers/promises');

const promise1 = setTimeout(100).then(() => { throw new Error('Promise 1 rejected'); });
const promise2 = setTimeout(200, 'Promise 2 resolved');
const promise3 = setTimeout(300).then(() => { throw new Error('Promise 3 rejected'); });

async function examplePromiseAny() {
  try {
    const result = await Promise.any([promise1, promise2, promise3]);
    console.log(result); // Expected output: "Promise 2 resolved"
  } catch (error) {
    console.error(error);
  }
}

examplePromiseAny();

promise_race.js

// Promise.race is settled as soon as any of the promises you feed it settle, whether they are fulfilled or rejected.
const { setTimeout } = require('timers/promises');

const promise1 = setTimeout(100, 'Promise 1 resolved');
const promise2 = setTimeout(200).then(() => { throw new Error('Promise 2 rejected'); });
const promise3 = setTimeout(300, 'Promise 3 resolved');

async function examplePromiseRace() {
  try {
    const result = await Promise.race([promise1, promise2, promise3]);
    console.log(result); // Expected output: "Promise 1 resolved"
  } catch (error) {
    console.error(error);
  }
}

examplePromiseRace();

promise_race_reject.js

// Promise.race is settled as soon as any of the promises you feed it settle, whether they are fulfilled or rejected.
const { setTimeout } = require('timers/promises');

const promise1 = setTimeout(100).then(() => { throw new Error('Promise 1 rejected'); });
const promise2 = setTimeout(200, 'Promise 2 resolved');
const promise3 = setTimeout(300, 'Promise 3 resolved');

async function examplePromiseRaceWithRejection() {
  try {
    const result = await Promise.race([promise1, promise2, promise3]);
    console.log(result);
  } catch (error) {
    console.error(error.message); // Expected output: "Promise 1 rejected"
  }
}

examplePromiseRaceWithRejection();